An inventory of multipurpose Avenue trees of Urban Chandigarh, India

Trees in urban ecosystems play a very significant role in environmental protection by checking air and noise pollntants, abating wind, and handling many other functions, in India, Chandigarh is the mosl modern and em,iromnentally safe city and qualifies to be called a GREEN CITY because of its rich tree component. This is so in spite of its high population density, currently over 9,443 people per square kin, perhaps the highest in the country. It has nearly 42,000 trees growing along the roads in a systematic manner. The drives are identified with the type of multipurpose tree species. Nearly 66 tree species (over half indigenous) are seen along the roadsides; these trees provide shade, timber, fuel, fodder, fruit, medicine, and other benefits. In addition, the city is decorated with 11 gardens harboring over 200 types of trees

ALLELOPATHIC IMPACT OF ESSENTIAL OIL OF TAGETES MINUTA ON COMMON AGRICULTURAL AND WASTELAND WEEDS

ABSTRACTObjective: Tagetes minuta (Family Asteraceae) is an aromatic plant possessing volatile essential oil.  Its oil finds extensive use in flavor and perfume industry. T. minuta oil also possess medicinal and insecticidal properties as antiheminthic, nematicidal, bactericidal, antiviral, fngicidal and insecticidal. The plant has been explored for herbicidal potential in very few reports. The aim of present study is to find out its allelopathic potential against common wasteland and agricultural weeds.Material & Methods: Various agricultural and wasteland weeds were selected for laboratory growth studies. Oil was applied in solution form using an emulsifier.Results: Growth of all test weeds was inhibited by T. minuta oil; however, effect was maximum in Amaranthus tricolor with complete inhibition at 1µl/ml and E. cruss-galli was least affected with complete inhibition at 5µl/ml concentration of T. minuta oil.Conclusion: T. minuta oil offers great potential for effective weed management in agricultural as well as wasteland areas. Keyowrds: Tagetes minuta, essential oil, allelopathy, solution form, wasteland, agricultural, weed

Phytotoxic potential of Populus deltoides Bartr. ex Marsh. I. Comparative contribution of different parts

The aqueous leachates prepared from different parts of Populus deltoides retard the germination and growth of mung bean (Phaseolus anrenus) However, the impact varied depending upon concentration and tree part used. The leachates prepared from leaves exhibited strong inhibitory potential compared to other parts. viz. bark. buds. root and stem. Since diflerent parts possess different water contents. The leachates prepared from fresh tree parts were equalized on the basis of dry weights. The content of organic component of leachable allelochemics (aglycones) depict a great variability with maximum amount being extracted from leaves and least from Stem. The relative allelopathic potentiality of each part was concomitant with respective amounts of aglycones in each part

Allelopathic interference of Populus deltoides with some winter season crops

Abstract -The performance of some winter season crops, namely Triticum aestivum, Lens culinaris, Phaseolus mungo, Avena sativa, Trifolium alexandrinum, Brassica juncea and Helianthus annuus was studied in association with Populus deltoides under alley cropping practice in two sets of fields in Punjab, North India. In one, the parent soil was retained (S p ), while in the other, the parent soil was replaced with soil collected from an area devoid of P. deltoides trees (S r ). Germination, plant height and biomass of the crops at 30 and 60 days after sowing (DAS) were reduced by 10 to 30% in both the P. deltoides fields compared to the ones without trees (S c ). The observed reduction was more pronounced in S p fields than in S r fields. Maximum reduction was observed in the case of B. juncea and least in T. alexandrinum. Germination and seedling growth of all the test crops except A. sativa and T. aestivum was found to be significantly reduced in response to the aqueous leachates of P. deltoides leaves. Likewise, the seedling length and dry weight of L. culinaris and T. aestivum were significantly reduced in litter amended soil. Litter and soil from P. deltoides fields were found to be rich in phytotoxic phenolics, the amount of which was more in S p fields compared to S r and control fields (S c ). Based on the study, the observed reductions could be attributed to the allelopathic interference of the tree with the crops through the release of phytotoxic phenolics from leaves and litter, which are continuously added to the soil. Dans l'un des groupes le sol d'origine a été conservé (S p ), tandis que dans l'autre il a été remplacé par un sol prélevé dans un endroit dépourvu de peupliers (S r ). La germination, la taille des plantes et la biomasse des cultures 30 et 60 jours après le semis ont été réduites de 10 à 30 % dans les deux groupes de champs comparativement aux champs sans peupliers (S c ). La réduction observée était plus forte dans les champs S p que dans les S r . La réduction maximum a eu lieu pour les cultures de B. juncea et, à un moindre degré, pour T. alexandrinum. Des filtrats aqueux de feuilles de P. deltoides ont réduit significativement la germination et la croissance des pousses de toutes les cultures testées, à l'exception de A. sativa et T. aestivum. De même, la longueur des pousses et le poids sec des cultures de L. culinaris et T. aestivum ont été significativement réduits dans le sol amendé par de la litière. Nous avons trouvé que la litière et le sol des champs de P. deltoides sont riches en substances phénoliques phytotoxiques ; les quantités sont plus importantes dans les champs S p que dans les S r et les témoins (S c ). Selon cette étude les réductions observées peuvent être attribuées à l'interfé-rence allélopathique du peuplier avec les cultures par l'intermédiaire de substances phénoliques phytotoxiques provenant des feuilles et de la litière, qui s'incorporent continuellement au sol

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

Allelopathic effect of two volatile monoterpenes against bill goat weed (Ageratum conyzoides L.)

A study was conducted to assess the allelopathic effect of two volatile monoterpenes viz. cineole and citronellol on Ageratum conyzoides with a view to explore the possibility of their exploitation for future weed management. Both the monoterpenes severely affected the germination, speed of germination, seedling growth, chlorophyll content and respiratory activity. After two weeks of exposure, the weed plants wilted. Out of the two monoterpenes, cineole was more toxic in causing injury to the weed

Eucalypt oils for the control of Parthenium (Parthenium hysterophorus L.)

Eucalypt oils from Eucalyptus globulus and E. citriodora exert deleterious effects on Parthenium hysterophorus - a noxious weed. The germination of the weed was inhibited and the chlorophyll content and cellular respiration of the mature plants exposed to eucalypt oils were reduced drastically. This was accompanied by increased water loss resulting in complete wilting of the plants after 15 days of exposure to volatile oils. The oil from E. citriodora was more effective in causing injury to the weed compared to E. globulus oil. Efforts should, therefore, be made to devise a strategy for controlling the weed through eucalypt oils

Phytotoxicity of a medicinal plant, Anisomeles indica, against Phalaris minor and its potential use as natural herbicide in wheat fields

Anisomeles indica (Catmint; Lamiaceae) is an aromatic plant with a wide range of medicinal properties. In the search of new methods of weed management, we assessed A. indica for potential inhibitory activity against P. minor and other weeds of the wheat crop. A. indica leaf and root powder applied as mulch at 1 and 2 t ha-1 significantly reduced the emergence and growth of P. minor and other weeds of wheat crop similar to herbicide, without any negative effect on the wheat growth and yield. At 2 t ha-1 dose of root powder mulch of A. indica, there was an enhancement in the grain yield of wheat and suppression of weeds under natural field conditions. The study concludes that mulch of A. indica, a medicinal plant, holds good promise for use as a natural herbicide for managing weeds in wheat fields